The central Quad of Harvard Medical School. Children's Hospital is adjacent to the buildings on the right.

Children's Hospital and Harvard Medical School are part of a larger, roughly 20 square block campus called the Longwood Medical Area. Children's sits in the center of this area, adjacent to the Brigham and Women's Hospital, Beth Israel Deaconess Medical Center and the Dana-Farber Cancer Institute, as well as Harvard Medical School, and within a block of the Joslin Diabetes Center, the Massachusetts College of Pharmacy, the Harvard School of Public Health, the Harvard Dental School and the Channing Laboratory. Some members of the staff are also staff members at one of these neighboring institutions.

Children's Hospital Boston participates in numerous cooperative programs. It is a partner in Neonatology with Brigham and Women's Hospital and Beth Israel Deaconess Medical Center. It is the headquarters of the New England Regional Infant Cardiac Program, the site of the Massachusetts Poison Control System, a partner in the Joint Program in Pediatric Hematology/Oncology with Dana-Farber Cancer Institute and a partner in the Joint Program in Gastroenterology and Nutrition with Massachusetts General Hospital across town. Several surgical departments are joint programs with the Brigham and Women's Hospital.

Recently, the Immune Disease Institute , which is partly located in the Harvard Medical School buildings, joined with Children's Hospital to become the Program in Cellular and Molecular Medicine. The IDI/PCMM, which originated at Children's Hospital years ago as the Blood Grouping Laboratory, is, in a sense, coming home. The Program has 19 principal investigators and 200 staff who pursue basic research in four principal areas: adhesion molecules and inflammation, autoimmune and allergic disease, genetics of immunodeficiency and cancer, and immune defenses against infectious disease and tumors.